Java Glossary : JIT

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JIT

Just In Time compiler. Compiling to native code just before the program runs. The results might be cached, but typically no permanent *.exe file is created. Contrast that with a native mode compiler. You get better debugging stack traces with the JIT turned off, and typically you get fewer JVM bugs.

In java.exe sometimes you can turn off the jit like this:

java.exe -Djava.compiler=NONE HelloWorld

make sure the -D option comes first, or it will be taken as a parameter to HelloWorld.

With Symantec, you can turn the JIT feature on and off this way:

REM use JIT
SET JAVA_COMPCMD=
REM use Interpreter
SET JAVA_COMPCMD=DIS

Unfortunately, capturing these commands in a BAT file has no effect since environment changes are discarded as soon as the bat file finishes.

In Netscape, you can turn the JIT feature on and off this way:

@echo off
rem jiton:jitoff d:
cd"Program Files\Netscape\Communicator\Program\Java\bin"
if"%1"=="on"rename jit3240.off jit3240.dll>NUL
if"%1"=="off"rename jit3240.dll jit3240.off>NUL
if exist jit3240.dll echo jit now on
if exist jit3240.off echo jit now off
rem -30-

CACAO ¤ Café ¤ compiler ¤ HotSpot ¤ interpreter ¤ JVM ¤ Kaffe ¤ native compiler

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